The present invention relates to late transition metal complexes, a process for their preparation and their use in the polymerization of olefins.
The papers in Organometallics, 10, 1421-1431, 1991; Inorg. Chem., 34, 4092-4105, 1995; J. Organomet. Chem., 527(1-2), 263-276,1997; and Inorg. Chem., 35(6), 1518-28, 1996, report the reaction of bis (iminophosphoranyl) methane (BIPM) which are typically aryl substituted on the phosphorus atom and the nitrogen with Group 8, 9 or 10 metal halides (chlorides) further comprising at two weakly coordinating ligands (L) such as nitrites or cyclooctadiene, afforded several products depending on the reaction time, type of ligand or nature of the metal. The product could be a N-C chelating type product or a N-N chelating product (similar to those of the present invention). 
The products contain alkyl bridges between the phosphinimine groups and the references do not disclose the pyridyl bridged compounds of the present invention. Further, none of the references teach or suggest the use of such compounds for the polymerization of alpha olefins.
U.S. Pat. No. 5,557,023 issued September, 1996 teaches the use of some phosphinimines complexes to oligomerize alpha olefins. However, the complexes disclosed are not bisphosphinimine complexes. Rather, the complexes are of the structure indicated below. 
wherein R, Q, etc. are as defined in the patent. The structures disclosed in the patent are not the bisphosphinimines of the present invention. While the reference does teach oligomerization, it does not suggest polymerization.
WO 98/30609 patent application published Jul. 16, 1998 assigned to E. I. du Pont de Nemours teaches the use of various complexes of nickel to polymerize alpha olefins. The most structurally similar complex in the disclosure is compound XXXXI at the middle of page 9 and the associated description of the various substituents. However, the compound does not contain a pyridyl bridge. Rather, the nickel atom completes the cyclic structure in the middle of the compound. The reference does not contemplate or disclose compounds of the present invention which have a pyridyl bridge between the bisphosphinimine functionality. The reference fails to disclose the subject matter of the present invention.
There are a number of patents and papers by Brookhart and/or Gibson disclosing the use of Group 8, 9 or 10 metals to polymerize olefins. However, such papers did not teach the copolymerizations (e.g. WO 98/27124). The present invention provides olefin copolymerization using an iron based catalyst.
The present invention provides a process for the polymerization of one or more C2-12 alpha olefins in the presence of an activatable complex of a Group 8, 9 or 10 metal and ligand of formula I: 
wherein R2, R3, R4 and R5 are independently selected from the group consisting of a hydrocarbyl radical which is unsubstituted, further substituted or an inert functional group; R6 and R7 are independently selected from the group consisting of a hydrocarbyl radical which is unsubstituted or further substituted, trialkyl silyl radical and an inert functional group; and R8, R9 and R10 are independently selected from the group consisting of a hydrogen atom, a hydrocarbyl radical which is unsubstituted or further substituted and an inert functional group.
A further aspect of the present invention provides a process for the polymerization of one or more C2-12 alpha olefins in the presence of:
(a) a complex comprising a Group 8, 9 or 10 metal and ligand of formula I: 
wherein R2, R3, R4 and R5 are each independently selected from the group consisting of hydrocarbyl, substituted hydrocarbyl or an inert functional group; R6 and R7 are each independently selected from hydrocarbyl, substituted hydrocarbyl, trialkyl silyl and substituted or unsubstituted aryl; and R8, R9 and R10 are each independently selected from hydrogen, hydrocarbyl, substituted hydrocarbyl, an inert functional group; and
(b) an activator at a temperature from 20 to 250xc2x0 C. and at a pressure from 15 to 15000 psi.
In a further aspect, the present invention provides a process for reacting one or more C2-12 alpha olefins in the presence of a catalyst of formula III: 
wherein R2 to R10 and M are defined above; L1 is a neutral monodenate ligand which is displaced by one or more of an activator, a scavenger or a monomer; x is from 0 to 12; L2 is an activatable ligand; and y is the oxidation state of the metal; with an activator at a temperature from 20 to 250xc2x0 C. and at a pressure from 15 to 15000 psi.
The present invention further comprises reacting a compound of formula II: 
wherein R2, R3, R4, R5, R6, R7, R8, R9, R10 and M are as defined above, X is a halogen and n is an integer from 1 to 3 with an alkylating agent at a temperature from xe2x88x9250 to 250xc2x0 C. to produce a compound of formula III as defined above.
The present invention also provides an olefin co- or homopolymer having a weight average molecular weight (Mw) from 5xc3x97104 to 107 and a degree of short chain branching from 1-30 per 1000 carbon atoms prepared in the presence of an iron (or cobalt) containing catalyst.
The term xe2x80x9cscavengerxe2x80x9d as used in this specification is meant to include those compounds effective for removing polar impurities from the reaction solvent. Such impurities can be inadvertently introduced with any of the polymerization reaction components, particularly with solvent, monomer and catalyst feed; and can adversely affect catalyst activity and stability. It can result in decreasing or even elimination of catalytic activity, particularly when an activator capable of ionizing the Group 8, 9 or 10 metal complex is also present.
The term xe2x80x9can inert functional groupxe2x80x9d means a functional group on a ligand or substituent which does not participate or react in the polymerization reaction. For example, in the polymerization aspect of the present invention an inert functional group would not react with any of the monomers, the activator or the scavenger of the present invention. Similarly for the alkylation of the metal complex or the formation of the metal complex the inert functional group would not interfere with the alkylation reaction or the formation of the metal complex respectively.
The phrase xe2x80x9ca neutral monodenate ligandxe2x80x9d means a ligand which is only loosely bound to the metal by a coordinative bond. These may include water (H2O) or tetrahydrofuran (THF).
As used in this specification, an activatable ligand is a ligand removed or transformed by an activator. These include anionic substituents and/or bound ligands. Exemplary activatable ligands are independently selected from the group consisting of a hydrogen atom, a halogen atom, a C1-10 hydrocarbyl radical, a C1-10 alkoxy radical, a C5-10 aryl oxide radical; each of which said hydrocarbyl, alkoxy, and aryl oxide radicals may be unsubstituted by or further substituted by a halogen atom, a C1-8 alkyl radical, a C1-8 alkoxy radical, a C6-10 aryl or aryl oxy radical, an amido radical which is unsubstituted or substituted by up to two C1-8 alkyl radicals, and a phosphido radical which is unsubstituted or substituted by up to two C1-8 alkyl radicals.
In the above compounds formula I-III, R2, R3, R4 and R5 are independently selected from the group consisting of a hydrocarbyl radical and an inert functional group. Preferably R2, R3, R4 and R5 are selected from the group consisting of C1-10 alkyl or aryl radicals, most preferably C1-4 radicals such as a bulky t-butyl radical and phenyl radicals. In the above compounds, R8, R9 and R10 are independently selected from the group consisting of a hydrogen atom, a hydrocarbyl radical which is unsubstituted or further substituted and an inert functional group, preferably a hydrogen atom and a C1-10, most preferably a C1-4 alkyl radical. In the above formula, R6 and R7 are independently selected from the group consisting of a hydrocarbyl radical, preferably a phenyl radical which is unsubstituted or substituted by up to five hydrocarbyl radicals, or a C1-10 alkyl radical, or two hydrocarbyl radicals taken together may form a ring, or a trialkyl, preferably C1-6, most preferably C1-4 silyl radical. In the complex of formula III, R2 through R10 are as defined above and L1 is a neutral monodenate ligand easily displaced by one or more of a scavenger, activator or monomer, preferably water or tetrahydrofuran. L2 is an activatable ligand, preferably a halogen or a C1-6 alkyl or alkoxide radical, most preferably a chloride, bromide, or a C1-4 alkyl or alkoxide radical; x is from 0 to 12, preferably from 0 to 6; and y is the oxidation state of the metal M, preferably 2 or 3.
In the compound of formula I and III, preferably R8, R9 and R10 are independently selected from the group consisting of a hydrogen atom or a hydrocarbyl radical, preferably a hydrogen atom and a C1-4 alkyl radical; R4, R5, R2 and R3 are independently selected from the group consisting of a hydrocarbyl radical which is unsubstituted or further substituted and an inert functional group; and R6 and R7 are independently selected from the group consisting of trimethyl silyl and an aryl radical, preferably from 6 to 14 carbon atoms which is unsubstituted or substituted by one or more radicals selected from the group consisting of C1-6 hydrocarbyl radicals, most preferably 2,6-di-isopropyl phenyl radicals. In a particularly preferred aspect of the present invention R8, R9 and R10 are the same; R2, R3, R4 and R5 are the same; and R6 and R7 are the same.
In the compound of formula II, preferred substituents for R2, R3, R4, R5, R6, R7, R8, R9 and R10 are as defined immediately above.
The metal complexes of the present invention may be prepared by reacting the ligand with a compound of MXn.A (H2O) X, wherein X may be selected from the group consisting of halogen, C1-6 alkoxide, nitrate or sulfate, preferably halide and most preferably chloride or bromide; and A is 0 or an integer from 1-6.
The reaction of the ligand of formula I with the compound of the formula MXn.A (H2O) may be conducted in a hydrocarbyl solvent at temperature from xe2x88x9250 to 250xc2x0 C., preferably from 20 to 120xc2x0 C.
The resulting compound may then be alkylated (either partially or fully). Some alkylating agents are Grignard agents of the formula RMgX and organolithium reagents LiR wherein R is a C1-10 alkyl radical and X is a halogen and alkyl aluminum reagents. Alkyl aluminum reagents include trialkyl aluminum, alkyl aluminum halides (i.e. (R)xALX3-x wherein R is a C1-10 alkyl radical, X is a halogen, x is 1 or 2 and MAO as described below).
Solution polymerization processes are fairly well known in the art. These processes are conducted in the presence of an inert hydrocarbon solvent typically a C5-12 hydrocarbon which may be unsubstituted or substituted by C1-4 alkyl group such as pentane, hexane, heptane, octane, cyclohexane, methylcyclohexane or hydrogenated naphtha. An additional solvent is Isopar E (C8-12 aliphatic solvent, Exxon Chemical Co.).
The polymerization may be conducted at temperatures from about 20 to about 250xc2x0 C. Depending on the product being made, this temperature may be relatively low such as from 20 to about 180xc2x0 C. The pressure of the reaction may be as high as about 15,000 psig for the older high pressure processes or may range from about 15 to 4,500 psig.
Suitable olefin monomers may be ethylene and C3-20 mono- and di-olefins. Preferred monomers include ethylene and C3-12 alpha olefins which are unsubstituted or substituted by up to two C1-6 alkyl radicals. Illustrative non-limiting examples of such alpha-olefins are one or more of propylene, 1-butene, 1-pentene, 1-hexene, 1-octene and 1-decene.
The reaction product of the present invention, in the presence of a single alpha olefin, may be an oligomer having a molecular weight (Mw) less than about 1500. The reaction product of the present invention may also be a co- or homopolymer of one or more alpha olefins. The polymers prepared in accordance with the present invention have a good molecular weight. That is, weight average molecular weight (Mw) will preferably be greater than about 50,000 ranging up to 107, preferably 105 to 107.
The polyethylene polymers which may be prepared in accordance with the present invention typically comprise not less than 60, preferably not less than 70, most preferably not less than 80 weight % of ethylene and the balance of one or more C4-10 alpha olefins, preferably selected from the group consisting of 1-butene, 1-hexene and 1-octene. The polyethylene prepared in accordance with the present invention may contain branching (e.g. one or more branches per 1000 carbon atoms, preferably 1-30 branches per 1000 carbon atoms, typical 1-20 branches per 1000 carbon atoms and most preferably 1-10 branches per 1000 carbon atoms).
The activator may be selected from the group consisting of:
(i) an aluminoxane; and
(ii) an activator capable of ionizing the Group 8, 9 or 10 metal complex (which may be used in combination with an alkylating activator).
The aluminoxane activator may be of the formula (R20)2AlO(R20AlO)mAl(R20)2 wherein each R20 is independently selected from the group consisting of C1-20 hydrocarbyl radicals, m is from 0 to 50, and preferably R20 is a C1-4 alkyl radical and m is from 5 to 30. The aluminoxane activator may be used prior to the reaction but preferably in situ alkylation is typical (e.g. alkyl groups replacing leaving ligands, hydrogen or halide groups).
If the Group 8, 9 or 10 metal complex is activated only with aluminoxane, the amount of aluminoxane will depend on the reactivity of the alkylating agent. Activation with aluminoxane generally requires a molar ratio of aluminum in the activator to the Group 8, 9 or 10 metal in the complex from 20:1 to 1000:1. MAO may be the higher end of the above noted range.
The activator of the present invention may be a combination of an art alkylating activator which also serves as a scavenger other than aluminoxane in combination with an activator capable of ionizing the Group 8, 9 or 10 complex.
The alkylating activator (which may also serve as a scavenger) may be selected from the group consisting of: (R)pMgX2xe2x88x92p wherein X is a halide, each R is independently selected from the group consisting of C1-10 alkyl radicals, preferably C1-8 alkyl radicals and p is 1 or 2; RLi wherein R is as defined above; (R)qZnX2xe2x88x92q wherein R is as defined above, X is halogen and q is 1 or 2; (R)sAlX3xe2x88x92s wherein R is as defined above, X is halogen and s is an integer from 1 to 3. Preferably, in the above compounds R is a C1-4 alkyl radical and X is chlorine. Commercially available compounds include triethyl aluminum (TEAL), diethyl aluminum chloride (DEAC), dibutyl magnesium ((Bu)2Mg) and butyl ethyl magnesium (BuEtMg or BuMgEt).
The activator capable of ionizing the Group 8, 9 or 10 metal complex may be selected from the group consisting of:
(i) compounds of the formula [R15]+[B(R18)4]xe2x88x92 wherein B is a boron atom, R15 is a cyclic C5-7 aromatic cation or a triphenyl methyl cation and each R18 is independently selected from the group consisting of phenyl radicals which are unsubstituted or substituted with from 3 to 5 substituents selected from the group consisting of a fluorine atom, a C1-4 alkyl or alkoxy radical which is unsubstituted or substituted by a fluorine atom, and a silyl radical of the formula xe2x80x94Sixe2x80x94(R19)3 wherein each R19 is independently selected from the group consisting of a hydrogen atom and a C1-4 alkyl radical; and
(ii) compounds of the formula [(R16)tZH]+[[B(R18)4]xe2x88x92 wherein B is a boron atom, H is a hydrogen atom, Z is a nitrogen atom or phosphorus atom, t is 2 or 3 and R16 is selected from the group consisting of C1-8 alkyl radicals, a phenyl radical which is unsubstituted or substituted by up to three C1-4 alkyl radicals, or one R16 taken together with the nitrogen atom to form an anilinium radical and R18 is as defined above; and
(iii) compounds (activators) of the formula B(R18)3 wherein R18 is as defined above.
In the above compounds, preferably R18 is a pentafluorophenyl radical, R15 is a triphenylmethyl cation, Z is a nitrogen atom and R16 is a C1-4 alkyl radical or R16 taken together with the nitrogen atom to form an anilinium radical which is substituted by two C1-4 alkyl radicals.
The activator capable of ionizing the Group 8, 9 or 10 metal complex abstract one or more L1 ligands so as to ionize the Group 8, 9 or 10 metal center into a cation, but not to covalently bond with the Group 8, 9 or 10 metal; and to provide sufficient distance between the ionized Group 8, 9 or 10 metal and the ionizing activator to permit a polymerizable olefin to enter the resulting active site.
Examples of compounds capable of ionizing the Group 8, 9 or 10 metal complex include the following compounds:
triethylammonium tetra(phenyl)boron,
tripropylammonium tetra(phenyl)boron,
tri(n-butyl)ammonium tetra(phenyl)boron,
trimethylammonium tetra(p-tolyl)boron,
trimethylammonium tetra(o-tolyl)boron,
tributylammonium tetra(pentafluorophenyl)boron,
tributylammonium tetra(pentafluorophenyl)boron,
tri(n-butyl)ammonium tetra (o-tolyl)boron
N,N-dimethylanilinium tetra(phenyl)boron,
N,N-diethylanilinium tetra(phenyl)boron,
N,N-diethylanilinium tetra(phenyl)n-butylboron,
N,N-2,4,6-pentamethylanilinium tetra(phenyl)boron
di-(isopropyl)ammonium tetra(pentafluorophenyl)boron,
dicyclohexylammonium tetra (phenyl)boron
triphenylphosphonium tetra)phenyl)boron,
tri(methylphenyl)phosphonium tetra(phenyl)boron,
tri(dimethylphenyl)phosphonium tetra(phenyl)boron,
tropillium tetrakispentafluorophenyl borate,
triphenylmethylium tetrakispentafluorophenyl borate,
benzene (diazonium) tetrakispentafluorophenyl borate,
tropillium phenyltris-pentafluorophenyl borate,
triphenylmethylium phenyl-trispentafluorophenyl borate,
benzene (diazonium) phenyltrispentafluorophenyl borate,
tropillium tetrakis (2,3,5,6-tetrafluorophenyl) borate,
triphenylmethylium tetrakis (2,3,5,6-tetrafluorophenyl) borate,
benzene (diazonium) tetrakis (3,4,5-trifluorophenyl) borate,
tropillium tetrakis (3,4,5-trifluorophenyl) borate,
benzene (diazonium) tetrakis (3,4,5-trifluorophenyl) borate,
tropillinum tetrakis (1,2,2-trifluoroethenyl) borate,
triphenylmethylium tetrakis (1,2,2-trifluoroethenyl) borate,
benzene (diazonium) tetrakis (1,2,2-trifluoroethenyl) borate,
tropillium tetrakis (2,3,4,5-tetrafluorophenyl) borate,
triphenylmethylium tetrakis (2,3,4,5-tetrafluorophenyl) borate, and
benzene (diazonium) tetrakis (2,3,4,5-tetrafluorophehyl) borate.
Readily commercially available activators which are capable of ionizing the Group 8, 9 or 10 metal complexes include:
N,N-dimethylaniliumtetrakispentafluorophenyl borate;
triphenylmethylium tetrakispentafluorophenyl borate; and
trispentafluorophenyl boron.
If the Group 8, 9 or 10 metal complex is activated with a combination of an aluminum alkyl compound (generally other than aluminoxane), and a compound capable of ionizing the Group 8, 9 or 10 metal complex; the molar ratios of Group 8, 9 or 10 metal:metal in the alkylating agent (e.g. Al); metalloid (e.g. boron or phosphorus) in the activator capable of ionizing the Group 8, 9 or 10 metal complex (e.g. boron) may range from 1:1:1 to 1:100:5. Preferably, the alkylating activator is premixed/reacted with the Group 8, 9 or 10 metal complex and the resulting alkylated species is then reacted with the activator capable of ionizing the Group 8, 9 or 10 metal complex.
In a solution polymerization, the monomers are dissolved/dispersed in the solvent either prior to being fed to the reactor or for gaseous monomers, the monomer may be fed to the reactor so that it will dissolve in the reaction mixture. Prior to mixing, the solvent and monomers are generally purified to remove polar moieties. The polar moieties or catalyst poisons include water, oxygen, metal impurities, etc. Preferably steps are taken before provision of such into the reaction vessel, for example by chemical treatment or careful separation techniques after or during the synthesis or preparation of the various components. The feedstock purification prior to introduction into the reaction solvent follows standard practices in the art (e.g. molecular sieves, alumina beds and oxygen removal catalysts) are used for the purification of ethylene, alpha-olefin and optional diene. The solvent itself as well (e.g. cyclohexane and toluene) is similarly treated. In some instances, out of an abundance of caution, excess scavenging activators may be used in the polymerization process.
The feedstock may be heated prior to feeding into the reactor. However, in many instances it is desired to remove heat from the reactor so the feedstock may be at ambient temperature to help cool the reactor.
Generally, the catalyst components may be premixed in the solvent for the reaction or fed as separate streams to the reactor. In some instances premixing is desirable to provide a reaction time for the catalyst components prior to entering the reaction. Such an xe2x80x9cin line mixingxe2x80x9d technique is described in a number of patents in the name of DuPont Canada Inc. For example it is described in U.S. Pat. No. 5,589,555 issued Dec. 31, 1996.
The reactor may comprise a tube or serpentine reactor used in the xe2x80x9chigh pressurexe2x80x9d polymerizations or it may comprise one or more reactors or autoclaves. It is well known that the use in series of two such reactors each of which may be operated so as to achieve different polymer molecular weight characteristics. The residence time in the reactor system will depend on the design and the capacity of the reactor. Generally, the reactors should be operated under conditions to achieve a thorough mixing of the reactants. On leaving the reactor system, the solvent is removed and the resulting polymer is finished in a conventional manner.
The present invention will now be illustrated by the following examples in which unless otherwise specified weight means weight % and parts means parts by weight (e.g. grams).
Materials: 2,6-dibromopyridine, diethylphosphine (Et2PH), diphenylphosphine (Ph2PH), di-tert-butylphosphine chloride (t-Bu2PCl), iron (II) chloride (FeCl2), iron (II) chloride tetrahydrates (FeCl2.4(H2O)), iron (II) tetrafluoroborate hexahydrate (Fe(BF4)2.4H2O), iron (III) bromide (FeBr3), iron (III) chloride (FeCl3.6H2O), cobalt chloride (CoCl2), bis (benzonitrile) dichloropalladium (II) (PdCl2(PhCN)2), nickel (II) bromide (NiBr2), n-Butyl lithium (BuLi, 1.6M in hexane), and trimethylsilyl azide (TMSN3) were purchased from Aldrich Chemical Company, Inc. and Strem Chemical Inc. Solvents were prepared by passing through molecular sieves, de-oxo catalysts and alumina columns prior to use. Methylaluminoxane (PMAO-IP) (13.5 weight % of Al) was purchased from AKZO-NOBEL and used as supplied. 2,6-bis (diphenylphosphino)pyridine (Ic) was prepared using the method described in the literature (G. R. Newkome and D. C. Hager, J. Org. Chem., 43(5), 947,1978). Diimine-Nickel complex (VIII) was synthesized as described in the literature (L. K. Johnson, C. M. Killiam, M. Brookhart, J. Am. Chem. Soc., 117, 6414, 1995). The anhydrous toluene was purchased from Aldrich and purified over molecular sieves prior to use. B(C6F5)3 was purchased from Boulder Scientific Inc. and used without further purification.
Measurements: NMR spectra were recorded using a Bruker 200 MHz spectrometer. 1H NMR chemical shifts were reported with reference to tetramethylsilane. Polymer molecular weights and molecular weight distributions were measured by GPC (Waters 150-C.) at 140xc2x0 C. in 1,2,4-trichlorobenzene calibrated using polyethylene standards. DSC was conducted on a DSC 220 C from Seiko Instruments. The heating rate is 10xc2x0 C./minute from 0 to 200xc2x0 C. FT-IR was conducted on a Nicolet Model 750 Magna IR spectrometer. MI was measured on an automatic MI machine with model number of MP993 at 190xc2x0 C.
Operation: All synthesis and catalyst preparations were performed under nitrogen or argon using standard Schlenk techniques or in a dry-box.